Im about to give this a whirl. Should be interesting. Half an hour of research has revealed that its not exactly easy to accomplish this but we’ll give it a whirl anyway! 
Update: OS 9 is pure and total horseshite, as is Outlook 5 for it!
Update: SOLUTION!!!
How to extract email messages from OUtlook Express 5 on Mac OS9
Requirements: Paitence (lots), Entourage 2001, ImapSize (http://www.broobles.com/imapsize/download.php)
Open Entourage 2001 on the Mac, and import your OE profile. Once this is done you can drag the Message folders to the desktop. This will automatically save them into MBOX format. Once this is done. Move the MBOX files to the new machine, and use IMAPSize to convert them to eml messages. Then open Live Mail and import the emails.
